Jerome Miron/USA TODAY SportsWith a healthy and productive Devonte Fields this fall, TCU's defensive line could be an elite unit.

1. TCU (pre-spring ranking: 2): Devonte Fields appears to be back, which is a scary proposition for the rest of the Big 12. The 2012 Big 12 AP Defensive Player of the Year basically had a fruitless sophomore campaign, which ended with season-ending foot surgery. But this spring, defensive coordinator Dick Bumpas noted that Fields was making the plays he did as a freshman All-American. Even without Fields, this would be a good D-line, headlined by veteran tackles Chucky Hunter and Davion Pierson. But with Fields playing up to his potential, this line could be elite.

2. Oklahoma (1): Not only did the Sooners return the entire line that destroyed Alabama in the Allstate Sugar Bowl, they’ve added three redshirt freshmen who are clamoring for playing time. Charles Walker is the most athletic tackle on the roster, and he ran the fastest tackle 40 time (4.67 seconds) of the Bob Stoops era. Tackle Matt Romar quietly emerged this spring and could be on the verge of taking away snaps from some of the veterans inside. Ogbonnia Okoronkwo showed this spring he's yet another Sooner capable of getting to the quarterback off the edge. There's a debate on the best D-line in the league. There’s no debate on the deepest, with Oklahoma capable of going three-deep across the board.

3. Baylor (6): Coach Art Briles believes he has one of the best defensive lines in the country, and there's reason to believe he might be right. The Bears made the biggest jump on this list, thanks to the development of end Shawn Oakman and emergence of tackle Javonte Magee. Briles called the 6-foot-9 Oakman “unblockable” during the spring. Oakman already flashed plenty of potential last season as a sophomore, finishing sixth in the league with 12.5 tackles for loss. Magee, who might be the most highly-touted high school defender Briles has ever signed, sat out his freshman season while dealing with a personal issue. But he established himself this spring and could beat out returning starter Beau Blackshear. With former four-star signee Andrew Billings (who played as a true freshman) also poised for a big year at the other tackle spot, Briles could indeed be proven correct in the fall.

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4. Texas (3): The Longhorns boast two of the league’s blue-chip defensive linemen in end Cedric Reed and tackle Malcom Brown. But whether this unit rises to the top of the league will hinge on the supporting cast. If athletic end Shiro Davis and run-stuffing tackle Desmond Jackson play up to their potential, and the Longhorns can get a boost from incoming freshmen Derick Roberson and Poona Ford, this could be a foundational positional unit in Charlie Strong’s first season.

5. Kansas State (4): Like Texas, the Wildcats have two blue-chip pieces returning up front in All-Big 12 end Ryan Mueller and tackle Travis Britz. They’re banking they’ll soon be adding a third in Terrell Clinkscales, who will be arriving to Manhattan shortly. Clinkscales, whom the Wildcats snatched away from Nebraska, was the nation’s No. 4-rated juco DT, and at 315 pounds, could be the run-stuffer K-State currently lacks.

6. Oklahoma State (5): With so much turnover elsewhere, the Cowboys will be counting on their line to be their anchor defensively.There’s reason to believe it could be that and more. Sam Wren received votes for Big 12 Defensive Newcomer of the Year last season, while Emmanuel Ogbah garnered consideration for Big 12 Defensive Freshman of the Year. Throw in promising redshirt freshmen Vili Leveni, Ben Hughes and Vincent Taylor, who all showed signs this spring they might be ready to contribute, along with veterans James Castleman, Ofa Hautau and Jimmy Bean, and Oklahoma State could have the anchor up front it needs while the rest of the defense retools.

7. West Virginia (7): This will probably be the weakest area of West Virginia defense, but with their talent at linebacker, the Mountaineers don’t have to be great up front. Dontrill Hyman, Christian Brown and Kyle Rose are currently the starters coming out of the spring. But the player to watch up front is sophomore Darrien Howard, who rapidly progressed since having his redshirt pulled late in 2013. If Howard develops into an impact player, he could give the Mountaineers a huge jolt up front.

8. Texas Tech (9): The Red Raiders tried to get by this spring while awaiting the horde of defensive line help set to arrive this summer. All told, the Red Raiders signed four juco D-linemen, only one of which – Keland McElrath -- enrolled early (McElrath was hobbled by a stress fracture all spring to boot). To be better up front, Tech, which ranked ninth in run defense last fall, will need at least a couple of its juco transfers to hit.

9. Kansas (10): Keon Stowers quietly has become as one of the better tackles in the league. He was the defensive MVP of Kansas' spring game after collecting eight tackles from his defensive tackle spot, and he was voted captain for a second straight year. Stowers and linebacker Ben Heeney will lead a defense that returns nine starters and could surprise after gaining confidence from playing Oklahoma and Texas tough last season.

10: Iowa State (8): The Cyclones took it on the chin this spring, with projected D-line starters Rodney Coe and David Irving both getting kicked off the team. Iowa State got a boost shortly after spring ball ended when 2013 starting tackle Brandon Jensen changed his mind about leaving the team. The Cyclones should be solid at end with Cory Morrissey and Mitchell Meyers, but even with Jensen’s return, interior line depth is a major concern.

As we wait for the start of spring ball, we’re examining and ranking the positional situations of every team in the Big 12, continuing Monday with defensive line. Some of these outlooks will look different after the spring. But here’s how we see the defensive lines at the moment:

Kevin C. Cox/Getty ImagesOklahoma end Charles Tapper will lead the Big 12's best defensive line in 2014.

1. Oklahoma: D-line began as a weakness but quickly turned into a strength under first-year position coach Jerry Montgomery. End Charles Tapper was an All-Big 12 selection as a sophomore, and tackle Jordan Phillips was on his way to earning similar honors before a back injury ended his season prematurely. Both players are back. So is Geneo Grissom, who had three sacks in the bowl win over Alabama. Nose guard Jordan Wade earned a starting role late in 2013, and Chuka Ndulue will be a starter for a third season. Basically, the entire rotation returns. If Phillips rebounds from the injury, this could prove to be Oklahoma’s finest D-line since 2009, when NFL All-Pro Gerald McCoy roamed the middle.

2. TCU: DE Devonte Fields, the Associated Press’ Big 12 Defensive Player of the Year as a freshman in 2012, had an empty season in 2013 thanks to a suspension, then a season-ending foot injury. If Fields can return to the player he was, TCU will be formidable up front. Chucky Hunter was a second-team All-Big 12 pick inside last season, and he’ll be flanked by an array of experienced tackles in Davion Pierson and Tevin Lawson, who were all part of the rotation last season. Ends Terrell Lathan, James McFarland and Mike Tuaua, who combined for 11 sacks in 2013, all return as well. Even with DT Jon Lewis giving up football, TCU's D-line figures to be as deep as any in the league.

3. Texas: Cedric Reed, one of the best sack men in the Big 12 last season, returns after giving the NFL a cursory thought. The Longhorns have to replace Big 12 co-Defensive Player of the Year Jackson Jeffcoat on the other side, but ESPN 300 recruit Derick Roberson, the No. 8 DE in the Class of 2014, could help right away. The Longhorns should also be stout inside, with run-stuffing tackles Malcom Brown and Desmond Jackson back to clog the middle.

4. Kansas State: Ryan Mueller, who was eighth nationally with 11.5 sacks last season, comes back after a breakout All-Big 12 season. Travis Britz is an all-conference-caliber tackle and gives K-State one of the better one-two punches on the D-line in the league. Joining them will be Terrell Clinkscales, who was the No. 4 junior college DT in the 2014 class. The Wildcats pried Clinkscales away from Nebraska, and at 315 pounds he could be the perfect complement to Britz, who relies more on quickness.

John Rivera/Icon SMIBaylor defensive end Shawn Oakman will play a bigger role next season.

5. Oklahoma State: The Cowboys lose two-time All-Big 12 tackle Calvin Barnett. James Castleman, however, will be a three-year starter, and end Jimmy Bean had a career night in the Cotton Bowl with three tackles for loss. The key to the Cowboys fielding one of the better lines in the league again will be whether Ben Hughes, Vincent Taylor and/or Vili Leveni can emerge inside after redshirting in 2013. All three are promising prospects, especially Taylor, who was an ESPN 300 recruit in the 2013 class.

6. Baylor: The Bears feature two of the more intriguing defensive linemen in the league. DE Shawn Oakman, a former Penn State transfer with tremendous length at 6-foot-9, finished sixth in the league with 12.5 tackles for loss last season, but he tailed off in Big 12 play. Baylor will ask him to play a much bigger role along the line, and he has the potential to give the Bears a unique playmaker there. On the inside, Baylor will lean more on Andrew Billings, who was part of the DT rotation as a freshman. If both Billings and Oakman play up to their vast potential, Baylor could be a handful up front.

7. West Virginia: The Mountaineers lose two of three starters along the D-line, including second-team All-Big 12 end Will Clarke. West Virginia is hoping for big things from DE Kyle Rose, who played a lot as a sophomore. Dontrill Hyman will likely fill a starting role on the other side, though he could get pushed for time by Eric Kinsey and Noble Nwachukwu, who both will be in their third year in the program. The Mountaineers will lean on Christian Brown and Darrien Howard at nose guard. Howard was an ESPN 300 recruit last year and played as a freshman. There’s some talent and potential here.

8. Iowa State: Like Texas Tech, Iowa State loaded up on immediate defensive line help, signing three juco defensive ends in Dalyou Pierson, Terry Ayeni and Gabe Luna, who is enrolled already for spring ball. Those three together with All-Big 12 honorable-mention selection Cory Morrissey and sophomore Mitchell Meyers should give Iowa State a solid rotation at end. Rodney Coe, who started the last four games, will anchor the Cyclones inside.

9. Texas Tech: The Red Raiders lose their two best defensive linemen in Kerry Hyder and Dartwan Bush, and Tech got pushed around up front anyway last season. Coach Kliff Kingsbury recognized this deficiency and signed four juco defensive linemen, all of whom have a chance to play immediately. Of the returning linemen, Branden Jackson was by far the most productive, totaling nine tackles for loss and four sacks as a starter.

10. Kansas: Despite also losing two starters, the Jayhawks have experience up front. Defensive captain Keon Stowers is back after manning the middle in 2013. Ben Goodman returns as well in Kansas’ “buck” role, and he is coming off a very solid sophomore season. Goodman’s backup, Michael Reynolds, and rotation players Tedarian Johnson and Ty McKinney give the Jayhawks depth.